arm64: dts: ti: k3-am68-sk-base-board: Add uart pinmux

Define the wakeup uart pin-mux for completeness and add explicit
muxing for mcu_uart0. This allows the device tree usage in bootloader
and firmwares that can configure the same appropriately.
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Udit Kumar <u-kumar1@ti.com>
Link: https://lore.kernel.org/r/20230602153554.1571128-4-nm@ti.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/k3-am68-sk-base-board.dts

@@ -22,6 +22,8 @@ chosen {
 	};
 
 	aliases {
+		serial0 = &wkup_uart0;
+		serial1 = &mcu_uart0;
 		serial2 = &main_uart8;
 		mmc1 = &main_sdhci1;
 		can0 = &mcu_mcan0;
@@ -202,6 +204,15 @@ J721S2_IOPAD(0x08c, PIN_INPUT, 7) /* (T25) MCASP0_AXR7.GPIO0_35 */
 };
 
 &wkup_pmx2 {
+	wkup_uart0_pins_default: wkup-uart0-pins-default {
+		pinctrl-single,pins = <
+			J721S2_WKUP_IOPAD(0x070, PIN_INPUT, 0) /* (E25) WKUP_GPIO0_6.WKUP_UART0_CTSn */
+			J721S2_WKUP_IOPAD(0x074, PIN_OUTPUT, 0) /* (F28) WKUP_GPIO0_7.WKUP_UART0_RTSn */
+			J721S2_WKUP_IOPAD(0x048, PIN_INPUT, 0) /* (D28) WKUP_UART0_RXD */
+			J721S2_WKUP_IOPAD(0x04c, PIN_OUTPUT, 0) /* (D27) WKUP_UART0_TXD */
+		>;
+	};
+
 	mcu_cpsw_pins_default: mcu-cpsw-pins-default {
 		pinctrl-single,pins = <
 			J721S2_WKUP_IOPAD(0x02C, PIN_INPUT, 0) /* (B22) MCU_RGMII1_RD0 */
@@ -254,6 +265,13 @@ J721S2_WKUP_IOPAD(0x07c, PIN_INPUT, 0) /* (H26) WKUP_GPIO0_9.MCU_I2C1_SDA */
 		>;
 	};
 
+	mcu_uart0_pins_default: mcu-uart0-pins-default {
+		pinctrl-single,pins = <
+			J721S2_WKUP_IOPAD(0x08c, PIN_INPUT, 0) /* (C24) WKUP_GPIO0_13.MCU_UART0_RXD */
+			J721S2_WKUP_IOPAD(0x088, PIN_OUTPUT, 0) /* (C25) WKUP_GPIO0_12.MCU_UART0_TXD */
+		>;
+	};
+
 	mcu_rpi_header_gpio0_pins0_default: mcu-rpi-header-gpio0-pins0-default {
 		pinctrl-single,pins = <
 			J721S2_WKUP_IOPAD(0x118, PIN_INPUT, 7) /* (G25) WKUP_GPIO0_66 */
@@ -305,6 +323,14 @@ &wkup_gpio1 {
 
 &wkup_uart0 {
 	status = "reserved";
+	pinctrl-names = "default";
+	pinctrl-0 = <&wkup_uart0_pins_default>;
+};
+
+&mcu_uart0 {
+	status = "okay";
+	pinctrl-names = "default";
+	pinctrl-0 = <&mcu_uart0_pins_default>;
 };
 
 &main_uart8 {